“The idea is that you provide specialised services for favoured applications,” he told FactCheck.

“At the moment, that’s about providing zero-rating stuff on mobiles, so it doesn’t reach your monthly limit. But in future, it could be about providing faster access for certain selected services, such as video, than what you get on your regular internet.”

Why are we arguing about it?

Net neutrality means ISPs have to follow strict regulations. And, without these, there might be more potential for them to make money.

For instance, video streaming websites might pay them to prioritise their content. They could also charge consumers different prices, depending on the package they chose.

Supporters of net neutrality say regulations help prevent a ‘two-tier’ internet – with some people getting a limited or slower service.

Without neutrality, they say smaller web firms could struggle to compete against more established ones who have deals with ISPs.

On the other hand, ISPs claim that regulations slow down innovation because it makes networks less profitable.

Is net neutrality under threat?

In America, the Federal Communications Commission (FCC) has recently revealed plans to overturn the rules brought in under Obama.

The FCC’s chairman, Ajit Pai, said the proposals would make the federal government “stop micromanaging the internet”.

The plans are expected to be approved in December, amid lots of lobbying in Washington from the telecoms industry.

But there have been protests from many of the biggest web firms and outcry from thousands of consumers. More than half a million people have reportedly called Congress to register their objections.

Facebook vice president Erin Egan said the FCC proposal fails to “ensure the internet remains open for everyone”. She said Facebook would “work with all stakeholders committed to this principle”.

Likewise, Netflix has said the FCC plan “defies the will of millions of Americans”.

How about the UK?

The issue has been less controversial in the UK, partly because the ISP market is more competitive.

One British politician has pointed out: “Unlike in the UK, in some parts of the US consumers have no choice which ISP they use because only one offers a service in their area.”

That means – without net neutrality – some US consumers may have no choice but to accept whatever packages their ISP offers.

In the UK, net neutrality rules are enshrined in EU law.

But before this, all the major ISPs had already signed up to a voluntary Open Internet Code. This made promises such as not blocking services or damaging the services of competitors.

Recent EU rules were more thorough and have received both praise and criticism.

Joe McNamee, of the European Digital Rights, has said that Europe is “a global standard-setter in the defence of the open, competitive and neutral internet”.

But Konstantinos Stylianou from the University of Leeds School of Law said it was “overkill”. And the former head of Ofcom has warned that “over-prescriptive and detailed legislation may deliver the opposite of the intended effect”.

Will Brexit change anything?

Possibly.

After Brexit, EU net neutrality laws would no longer apply. It is also possible that the UK could leave Berec, the European regulator on neutrality.

The government has signaled that it intends to transfer the EU rules over to UK law.

However, it is possible that Parliament could make amendments before it is passed. People on both sides of the debate will no doubt try putting pressure on politicians.

And Professor Chris Marsden has warned that – if the UK is no longer in the European Economic Area (EEA) post-Brexit, and leaves Berec – that could lead to complications, particularly surrounding data protection rules.